Explosive



This invention relates to the art ofexplbsives and more particularly to a new type of explosive composition and to the production of explo-sive articles therefrom.

v As is well knownLthe proptti f commerical explosives require some sort ofpacltage for the explosive as ultimately utilized. For exai'npl; propellants or lovv lexplosives are usually packaged in metallic cartridges, primary explosives are `usually packaged in, metallic tube's'or shells to fort-n` initiating devices, and dynamiteand other high explosives Aare usuallyypckgkdin paper` containers.

The constituents chosen tofgive'an explosive fora spcific use may be selected from the classes listed above and maybe suitably formulated t obtain the characteristics desired for the,` sr'ieciiic'zuse.` However, in'general, a package or container is` required and these. mayvary insiz'e from a small cartridge or initiating device tofan extremely large shell` for large sie dynamite cartridges. The purpose of the container may be rnliltifold. It may serve s a'ureceptacle for the explosive alone or Vreceive additional components, provide waterproofiiess; cninement, ease of handling', etc. n has n w been 4 y osi onshavin'gfi the property of being selfcont'ained, thereby eliminating' the necessity of containers, and that these explosive composi-tions are `capable of being modified to cover a variety of explosive uses'.

geweten that iris pessime fo been In a'ccodnce with the present invention such explosive E compositions are produced' by the formation of the polymerization product of a uniform mixture of polymerizableV vinyl material and nonaromatic explosive material, selected from the gnou'p consisting of azides, 'organic nitrates 'and organic nitramines, the polymerization reaction taking' pla'ce in situ. Depending on the amount and type of explosive material employed, the polymerization products thus fonnedlrnaywbe either combustible or 4detonatabl'e' or both. Depending on the particular polymerizabl'e material employed, the polyinerization"r products will range from lle'xible, rubb'ery substances to hard, horny bodies. In any event, all explosive articles of the cornpositions of the invention will be free from detrimental volatile Vsubstituents a's compared to` prior art compositions wherein volatile solvents generally have been used in the preparation of explosive or combustible charges. The following examples illustrate various methods of carrying the invention into practical effect.

EXAMPLE 1 Preparation of propellant u The following composition was, mixed and poured into molds with removal of entrained ai'r. y Y

Weight percent Triton X-lGO 1 0.32 Lami11ac ,4l342 L 3L16 Diallylphthalate 28.10 Luperco ATAC* 'catalys`t3 p 1.26 Cyclorfe (through 60, on 80 mesh) 67.16

phenol.' l 21A llquidpolyester resin curing tol a.` flexible iol-m1..I f

as extender.

2 propellant was then polymerized andv cured'in situ at' 145 F. for 2 d ays'andat 185,F.V for 2' additional days. After cooling, the p'ropell'anty was removed from the molds andpotted' with aphigh temperature resistantinhibiting composition and each of the inhibited' grains was then cured. The inhibiting co'mpositionwas identical to the pi'ioptellantI composition the exception` that an inert material (K2SO4) was utilized in'lie ofthe cyclonite.

The single-(end burning grains kthusforrnved were fired in a 4-inch diameter heavy chamber'ed motor. The pnopellant' in each grain measured. 2.1%'2- inches. in diameter and- 4 inches in length. The' following. results were o'btained on each of four grains.

l l Griii'n Nettie 016111. `(i.) 0.052 0.055 1 0.059 1 0.003 Ayg. pressure (n 4 2,459 1.5.61.. 817 `792 Avgiburnigrarnn ec. 0.160 121 n 0.083 0.076

EXAMPLE 2 Prepari. of high 'explosive A ben'zoyl peroxide catalyst (10.40.06 was dissolved in 3 g'.m"ethy1mejihery1ate, yand 10 g. ofrpenaerythritd jtetr'anitrat' added to the solution. l The mixture was stirred` until `the pent'a'e'rythritpl tetranitr'ate was` thoroughly wet and then sufficient of the mixture was-placed in a 6 'inch length 'o f 0.3`0-Vin'ch inside diameter gl'ss tub- 'ingwt'o fill itvto a length of 5 inches. The mixture was packed ldownlightly` with a rodtakin'gea'retcf vvet the tube sidewalls thoroughly'.l fl`he tube was sealed at both ends 4rightly with Corrs wrapped in' aluminum Vroi-1 and placed' in an oven' at 50 C'. for 16' hours. Aftei curing -was completed, the charge was cooled and the sample cellulose acetate tubing:

Wei percent Pentaerythritol tetranitrate 60 Nitroglycerin (0.75% ethyl centralita-added) 2.4

Monomericmethyl methacrylate (0.5%.benzoyl pe'l'- oxide added) l2 Polymethyl methacrylate 4 The finely-ground polymethyl metha'crylate was put into solution with` the' monomeric methyl methacrylate,

landthen the remaining` ingredients mixed. together. The

charge was cured at 60 C.,for,20 hours. The tubing was strippedfrom the charge, and the bare fuse was found to be rubbcry and flexible.` `A six-inch` length was pn'med with an Army Engineers Special E.B. cap and placed on a lead plate. Upon tiring the capex'amination of the dent in the lead plate'indicated the fuse detonated completely. 1

EXAMPLE 4 Prparation of shirptii'clilrge A'mixtur: of 60 g, cyclonite andmllSg.,styrene-modified polyester, catalyzed with .1% tertiary butyl bildm- ,peroxide, was packed into a 10Q-cc. glass beaker (approx,

1% inches diameter x 2% inches deep). A copper cone made of IAQ; inch sheet, having a base of 1% inches and a height of 1% inches was forced down into the mixture (vertex down) until the level of the explosive-monomer mixture was even with the base of the cone. The charge was cured at 60 C. for 16 hours, and then removed from the glass mold. The charge was primed with a No. 6 E.B. cap, and the base placed two inches above (stand-olf distance) a series of steel plates. Upon detonation the jet from the shaped charge made a 31/2 inch deep hole in the steel plates.

EXAMPLE 5 Preparation of high explosive charge A mixture of 70% by weight pentaerythritol tetranitrate and 30% by weight of a styrene-modified polyester (containing 1% methyl ethyl ketone peroxide), where the styrene-polyester was composed of 30% styrene and 70% of the reaction product of 7.5 moles maleic anhydride, 2.5 moles phthalic anhydride, 2.75 moles ethylene glycol and 8.25 moles diethylene glycol, was charged into a Z-inch outside diameter by 3-inch long aluminum mold and cured 16 hours at 50 C. Upon removal from the mold, and after cooling, the resultant charge detonated completely with a No. 6 E.B. cap.

EXAMPLE 6 Preparation of explosive casing A mixture of 65% by weight cyclonite and 35% by weight of a styrene-modified polyester (containing 1% methyl ethyl ketone peroxide and 1/z% of cobalt naphthenate), where the styrene-polyester was composed of 30% styrene and 70% of the reaction product of 7 moles maleic anhydride, 1.5 moles phthalic anhydride, 1.5 moles adipic acid, 5.5 moles ethylene glycol, 5.5 moles diethylene glycol, was charged into a 3-inch outside diameter, 1% inch inside diameter by 3-inch long aluminum mold and cured 4 hours at 25 C. Upon removal from the mold, the case was loaded with 50/50 pentolite and detonated with a No. 8 E B. cap. The case detonated completely.

EXAMPLE 7 Preparation of explosive charge A mixture of 60% by weight cyclonite and 40% by weight of a mixture composed of 84% ethyl methacrylate monomer, 15% nitrocellulose (1/2 sec. viscosity) and 1% benzoyl peroxide, was cast into a glass test tube and cured at 50 C. The resultant material was hard and strong and could be detonated completely with a No. 8 E.B. cap.

It will be noted from the above examples that the explosive compositions of this invention may be varied widely to fit specific uses. It -is Well known that the properties of synthetic addition polymers employed in the invention can be varied within wide limits depending on the extensive range of originating materials available and the conditions of reaction. However, it was quite unexpected to discover that these diicultly combustible materials in combination with explosive ingredients would yield efficient explosive compositions. Although itis not intended that the invention shall be limited to any particular theory of operation, it appears that the retention of the explosive material in dispersed or particulate form throughout the composition imparts properties not otherwise attainable. This applies to propellant explosives, initiating explosives, and high explosives. In accordance with the present invention such explosives have improved y thermal stability. This is important since it is sometimes necessary to submit explosives to high temperature conditions. rFor example, explosives when used as propellants in conjunction with oil well perforator guns are frequently subjected to high temperature zones where premature ignition would damage the casing wall or decline in propulsive strength would cause malfunctioning.

Moreover, high explosives are likewise subjected to conditions of high temperature such as those caused by uriderground fires in the vicinity of a borehole blasting operation or in the shooting ofdeep oil wells. It is appreciated that since the polymerization product encases the distinct particles of explosive that a certain degree of insulation relative to thermal conditions exists. Such a condition would indicate that combustion of the propellant explosives and detonation of the high explosives or initiating devices employing the composition would not be satisfactory. However, quite to the contrary it was found that explosives ranging from combustible types to detonative types could be produced satisfactorily. It is believed that having the explosive in distinct particles and encased within the polymerization product enhances the chemical transformation of these particles whether produced by heat or shock.

The compositions of the present invention may be produced by intimately and uniformly mixing polymerizable vinyl type materials with nonaromatic explosive material selected from the group consisting of azides, organic nitrates and organic nitramines and subsequently curing the same. The materials may first be mixed and cast in a suitable mold, added separately, or added together and mixed in the mold. Generally, the explosive composition thus produced will be removed from the mold in the shape of its intended use. In some instances, however, the mold may comprise the warhead of high-explosive ammunition or the like in which the explosive composition is retained. In other instances, where propellant-type explosive is desired, the composition may constitute an individual charge or it may be subsequently granulated after polymerization. In still other instances, the explosive composition may be cast or extruded on an endless belt and conveyed to a curing zone. This procedure is desirable in the formation of thin sheets or sections of rigid or flexible product, particularly where a considerable length is desired.

The polymerization products utilized in accordance with this invention may be polymers, copolymers, cross-linked addition polymers or mixtures thereof. The consistency of the polymerizable materials may vary from very fluid to pasty and the viscosity of these materials may be varied by mixture or by partial polymerization before use. Thus, polymeric methyl methacrylate may be dissolved in monomerio methyl methacrylate and the explosive material added. Generally, the materials for the polymerization reaction will be nonexplosive, although explosive mono-l meric materials are operable. Moreover, soluble explosive material may be added to the nonexplosive materials for the polymerization reaction providing that the material itself and the amount present do not inhibit the polymerization reaction. An example of such material is nitrocellulose which has shown satisfactory results when used in amounts as high as 65 by weight in solution with the nonexplosive material, such as methyl methacrylate, employed for the polymerization reaction. Similarly, other soluble explosive materials may be incorporated to provide fuel for the explosive composition as well as adjustment of the viscosity. Plastieizers may be added to modify the properties of the matrix if desired. Nonexplosive plasticizers include triacetin, alkyl phthalates such as dibutyland diamyl-phthalate, long chain adipates, and sebacates such as dihexyl sebacate and didecyl adipate.

Explosive plasticizers such as the liquid explosive nitric esters also may be employed.

In general, the polymerizable materials employed in preparing the compositions of the invention are monomeric or partially polymerized vinyl materials which readily form linear or cross-linked type polymers in the presence of a polymerization catalyst and at low temperatures. Materials which harden or cure by condensation type reaction are not operable in the invention since in general they require undesirably high temperatures foi the reaction and invariably evolve undesirable gaseous or liquid lay-products which adversely affect the physical properties of the nal product. aldehyde, urea-formaldehyde, or melamine type ofsynthetic resins and the like are excluded from the invention.

More specifically, the operable vinyl type polymerizable p materials include the acrylics such as methyl, ethyl and Thus, the phenol-form butyl acrylate or methacrylate; styrene, styrene-polyesters,

acrylonitrile, diallyl phthalate and the like. and the styrene-polyesters are preferred. styrene-polyesters will contain from about 30-70% styrene and from about 70-30% polyester. Preferred poly- The acrylics In general, `the esters are the reaction products of ethylene glycol, dieth- L may be polymerized in situ and have excellent castingcharacteristics with a cure rate adjustable over a wide range of temperature and time. Moreover, the polymerization reaction may be carried out under conditions of temperature and catalysis with temperatures from about 20 C. to not more than about 100 C. and with peroxidic catalysts such as benzoyl peroxide, lauroyl peroxide, methyl ethyl ketone peroxide and tertiary butyl hydroperoxide or catalysts such as di-tert-butyl diperphthalate and tert-butyl perbenzoate. The peroxidic catalysts vare preferred, and although the catalysts may be used in amount up to about 10%, the preferred amount is ordinarily about 1 to 5% by weight of the monomer being utilized. The cure time of these materials will vary from a few minutes to several days and the amount and type of catalyst may be selected to give the cure time desired for the particular resin.

As indicated, the explosive material which is admixed with the polymerizable vinyl material to form the polymerization products of the invention will be chosen from nonaromatic explosives selected from the group consisting of azides, organic nitrates and organic nitramines and will preferably be selected from the group consisting of nonaromatic crystalline high explosives such as ethylene dinitramine, methylene dinitramine, cyclotrimethylenetrinitramine (cyclonite) diethanolnitramine dinitrate, pentaerythritol tetranitrate, lead azide, silver azide, nitrolactose, sucrose octanitrate, lactose octanitrate and mannitol hexanitrate. Nitrocellulose in fibrous or filament form or in solution may also be employed` When it is desired to incorporate a liquid explosive in the composition, nitroglycerin or other liquid nitric ester may be employed. Aromatic explosive compounds are not operable in the invention since the aromatic nucleus inhibits polymerization of the vinyl material and prevents satisfactory consolidation of the charge. The amount of explosive material which may be present is subject to a wide range depending on the characteristics desired of the composition. The amount will range from about 50 to about 85%, and preferably from about 60 to about 80%, by weight of the explosive composition. With lowv amounts of explosive material present, very hard or very flexible compositions may be obtained which are diicultly detonatable and combustible. With high amounts of explosive material present, compositions may be obtained which are easily detonatable and combustible. The particle size of the solid explosive preferably should be such that substantially all passes through a 40-mesh screen although the particle size may be varied over wide limits. In general, the sensitivity of solid explosives to initiation is increased by lowering the particle size. Therefore, to increase sensithe explosive component.

organic compounds may be incorporated in the explosive compositions of this invention to the extent that the polymerization reaction is not unduly inhibited and the composition is not impaired in respect to its desired function. Such auxiliary agents may include reinforcing agents such as fiberglass, fillers, pigments, dyes, cellulose derivatives, natural resins, and the like. These agents may be employed to obtain certain desired physical and/or chemical characteristics in the intermediate as well as the end product.

It willbe seen, therefore, that this invention may be carried out by the use of various modifications and changes without departing from its spirit and scope.

VThe explosive compositions of this invention may be used in applications such as initiating devices, commercial blasting explosives, military explosives, propellants, gas generating charges, shaped charges, and fuses including ordinary and detonating types.

The advantages of the invention are numerous and include elimination of the necessity for containers, good thermal stability, good water resistance, controlled degrees of sensitiveness, and economies' in any 1 1se Wherathe` properties of the explosive composition permit the elimination of supporting components entirely, or a reduction in the structural requirement of such components, and provide an improved method for charging an explosive container including flexible tubing for fuses.

This application is a continuation-impart of application Serial No. 538,788 led October 5, 1955, now abandoned, which in turn is a continuation-in-part of application Serial No. 25,993 filed May 8, 1948, now abandoned.

What I claim and desire to protect by Letters Patent is:

l. As a new article of manufacture, an explosive unitary mass of a fissure-free synthetic waterproof, selfsustaining, resinous polymerization product which is the polymerized reaction product consisting essentially of from labout 50 to about 85% by weight of particulate nonaromatic crystalline high explosive of the group consisting of ethylene dinitramine, methylene dinitramine, cyclotrimethylenetrinitramine, diethanolnitramine dinitrate, pentaerythritol tetranitrate, lead azide, silver azide, nitrolactose, sucrose octanitrate, lactose octanitrate and mannitol hexanitrate in intimate and uniform mixture with from about 15 to about 50% by weight of catalyzed vinyl material of the group consisting of methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, styrene, styrene-polyester, acrylonitrile and diallyl phthalate, the reaction mass being shaped and polymerized in situ at a temperature from about 20 to about 100 C. to yield said polymerized reaction product.

2. As a new article of manufacture, an explosive unitary mass of a fissure-free synthetic waterproof, selfsustaining, resinous polymerization product which is the polymerized reaction product consisting essentially of from about 60 to about 80% by weight of particulate nonaromatic crystalline high explosive of the group consisting of ethylene dinitramine, methylene dinitramine, cyclotrimethylenetrinitramine, diethanolnitramine dinitrate, pentaerythritol tetranitrate, lead azide, silver azide, nitrolactose, sucrose octanitrate, lactose octanitrate and mannitol hexanitrate in intimate and uniform mixture with from about 20 to about 40% by weight of catalyzed vinyl material of the group consisting of methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, styrene, styrene-polyester, acrylonitrile and diallyl phthalate, the reaction mass being shaped and polymerized in situ at a temperature from about 20 to about 100 C. to yield said polymerized reaction product.

3. As a new article of manufacture, an explosive unitary mass of a fissure-free synthetic waterproof, self-sustaining, resinous polymerization product which is the polymerized reaction product consisting essentially of from about 60 to about 80% by weight of cyclotrimethylenetrinitramine in intimate and uniform mixture with from about 20 to about 40% by weight of catalyzed diallyl phthalate, the reaction mass being shaped and polymerized in situ at a temperature from about 20 to about 100 C. to yield said polymerized reaction product.

4. As a new article of manufacture, an explosive unitary mass of a fissure-free synthetic waterproof, selfsustaining, resinous polymerization product which is the polymerized reaction product consisting essentially of from about 60 to about 80% by weight of pentaerythritol tetranitrate in intimate and uniform mixture with from about 20 to about 40% by weight of catalyzed methylmethacrylate, the reaction mass being shaped and polymerized in situ at a temperature from about 20 to about 100 C. to yield said polymerized reaction product.

5. A's a new article of manufacture, an explosive unitary mass of a fissure-free synthetic waterproof, self-sustaining, resinous polymerization product which is the polymerized reaction product consisting essentially of from about 60 to about 80% by weight of pentaerythritol 30 tetranitrate in intimate and uniform mixture with from about 2O to about 40% by weight of catalyzed styrenepolyester, the-reaction mass being shaped and polymerized in lsitu at a temperature from labout 20 to about 100 C. to yield said polymerized reaction product.

6. As a new article of manufacture, an explosive unitary mass of a fissure-free synthetic waterproof, selfsustaining, resinous polymerization product which is Ithe polymerized reaction product consisting essentially of from about 60 to about 80% by weight of cyclotrimethylenetrinitramine in intimate and uniform mixture with from about 20 to about 40% by weight of catalyzed styrene-polyester, the reaction mass being shaped and polymerized in situ at a temperature from about 20 to about 100 C. to yield said polymerized reaction product.

7. As a new article of manufacture, an explosive unitary mass of a fissure-free synthetic waterproof, selfsustaining, resinous polymerization product which is the polymerized reaction product consisting essentially of from about V60 to about 80% by weight of cyclotrimethylenetrinitramine in intimate and uniform mixture with from about 20 to about 40% by weight of catalyzed ethyl methacrylate, the reaction mass being shaped and polymerized in situ at a temperature from about 20 to about 100 C. to yield said polymerized reaction product.

References Cited in the file of this patent UNITED STATES PATENTS 2,165,263 Holm July 11, 1939 FOREIGN PATENTS 655,585 Great Britain Aug. 31, 1948 

1. AS A NEW ARTICLE OF MANUFACTURE, AN EXPLOSIVE UNITARY MASS OF A FISSURE-FREE SYNTHETIC WATERPROOF, SELFSUSTAINING, RESINOUS POLYMERIZATION PRODUCT WHICH IS THE POLYMERIZED REACTION PRODUCT CONSISTING ESSENTIALLY OF FROM ABOUT 50 TO ABOUT 85% BY WEIGHT OF PARTICULATE NONAROMATIC CRYSTALLINE HIGH EXPLOSIVE OF THE GROUP CONSISTING OF ETHYLENE DINITRAMINE, METHYLENE DINITRAMINE, CYCLOTRIMETHYLENETRINITRAMINE, DIETHANOLNITRAMINE DINITRATE, PENTAERYTHRITOL TETRANITRATE, LEAD AZIDE, SILVER AZIDE, NITROLACTOSE, SUCROSE OCTANITRATE, LACTOSE OCTANITRATE AND MANNITOL HEXANITRATE IN INTIMATE AND UNIFORM MIXTURE WIT FROM ABOUT 15 TO ABOUT 50% BY WEIGHT OF CATALYZED VINYL MATERIAL OF THE GROUP CONSISTING OF METHYL ACRYLATE, ETHYL ACRYLATE, BUTYL ACRYLATE, METHYL METHACRYLATE, ETHYL METHACRYLATE, BUTYL METHACRYLATE, STYRENE, STYRENE-POLYESTER, ACRYLONITRILE AND DIALLYL PHTHALATE, AND REACTION MASS BEING SHAPED AND POLYMERIZED IN SITU AT A TEMPERATURE FROM ABOUT 20 TO ABOUT 100*C. TO YIELD SAID POLYMERIZED REACTION PRODUCT. 